Telephone-exchange system



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III

Patente Aug. 19, 1924..

ITE

PATENT OFFICE...

FRANKLIN A. STEARN, OF PATERSON, NEW JERSEY, A SSIGNOR T0 WESTERN ELECTRIC COIWPANY, INGORPORATEI), OF NEW YORK, N. Y., A CORPORATION OF NEW YO'RK.

' TELEPHONE-EXCHANGE sYs'rEM.

Application filed April 25, 1921; Serial No. 464,242.

To 7K whom it may concern:

Be it known that I, FRANKLIN' A. *STEARN, a citizen of the United States, residing at Paterson, in the county of Passaic, State of New Jersey, have invented certain new and useful Improvements in "Telephone Exchange Systems, of which the following is a full, clear, concise, and exact description.

This application relates to a telephone exchange system and more particularly to an office sending mechanism for controlling the establishment of connections through the medium of automatic switching mecha nism.

ln systems employing automatic switches of the power-driven revertive impulse type, it is the usual practice to provide a plurality I of common central office sending mechanisms for controlling the automatic switches, any idle one of which may be employed by a calling subscriber; Each office sending mechanism is provided with a set of code 'registers and a set of numerical registers upon which the calling subscriber registers the oilice designation and the numerical designation of a desired distant point, through the operation of his impulse dial. The sending mechanisms thereafter function to govern the selective movements of automatic switches in accordance with such registration. Since the office sending mechanism must replace the directing mind of the usual manual operator, it is necessary that the sending mechanism be so constituted that"it is enabled to care for any contingency that may arise.

It is. therefore, the object of the present invention to provide an oiiice sending mechanism of improved construction which is efiicient and reliable in operation.

One feature of the present invention re sides in the provision of means associated with the oiiice sending mechanism for automatically maintaining the resistance of'the fundamental or switch controlling circuit extending between the sending mechanism and the various switches or apparatus controlled thereby within specified working limits,.regardless of the destination of the initiated call for the purpose of insuring that the reciprocal control exercised between the sending mechanism and the connection extending apparatus shall be efficient under all conditions. This is accomplished by means of a istered on the coderegisters of the sending mechanism, and which,'in its several positionsrconnects resistance elements of different ohmic values into the fundamental circuit.

A second feature of the invention resides in the provision of means for cancelling the routing as designated by the code registers of the sending mechanism and for prescribing a special routing for extending a callingsubscribers line to a zero or special operators position, if the calling subscriber is entitled to restricted service only and attempts to establish a connection to which he is entitled only upon the payment of an extra rate. This is accomplished by a special route switch which is positioned by zone or route register relays and which re routes the attempted call in such a manner that the district and office selector switches function under the control of the route switch to extend a connection from the calling line to the operators position rather than to the zone or zones of the exchange into which the calling subscriber attempted to extend the connection.

A further feature resides in the provision of means for, enabling the ofiice' sending mechanism to send relay call indicator impulses to distant manual ofiices to indicate the designations of subscribers. lines which have numbers less than or greater than 10,000, by changing the order in which the several series of relay call indicator impulses are transmitted.

A still further feature of the invention I relates tomeans for increasing or decreasing the speed of operation of the sending mechanism dependent upon whether it is necessar for the calling subscriber to dial extra digits for obtaining party line or automatic branch exchange lines. This is accomplished by means of relays which are operated in accordance with the setting of the code registers and which are instrumental in introducing a delay in the functioning of the sending mechanism if the code dialed indi .cates that the subscriber will dial extra mechanism to ,normal'condition and for in-- suring that all seized apparatus shall be properly restored in the event that a calling subscriber abandons a call before obtaining a desired connection.

Suchother features as are contemplated by thepresent'in'vention will become more apparent. from the following description and the appended claims. The invention will now be described in connection with one specific embodiment of the genus thereof. In the accompanying drawings Fig. 1 shows one of a grou of lines terminating in a full mechanica oflice of the exchange and a rotary line switch individual to such line by means of which the subscribers line may be connected to an idle district selector switch;- Fig. 2 shows 'a'district selector and a sender finder switch together with the circuits and controlling mechanism associated therewith; Fig. 3 shows an ofiiceselector together with the circuits and controlling mechanism associated therewith; Fig. 4 shows an incoming selector switch provided with mechanism for applying ringing current to the terminals of a called line, together with the circuits and mechanism for controlling such switch; Fig. 5 shows the mechanism and circuits of a final selector switch and the line of a subscriber to which the selector switch has access; Fig. 6 shows the signaling circuits associated with the ofiice sender and terminating before the .monitoring'position of the trouble desk, and the circuits and apparatus for controlling the collection and refunding of coins deposited in the coin boxes of calling subscribers lines; Fig. shows a time measure switch and translator control sequence switch associated with the ofiice sending mechanism; Fig. 8 shows a' ters of the sender and the thousands and] hundreds numerical registers which are set in accordance with the first three code or oflice designation digits dialed by the calling subscriber and the first two numerical digits, and the steering switch which successively associates the registers shown in Flgs. 11 and 12 with the impulse circuit extending to the calling subscribers line; Fig. 12

shows the tens and units numerical registers and three stations registers, which registers are under the control of the steering switch tablished-by a calling subscriber b relay' and impulse circuit disclosed in Fig. 11;

Figs. 13 and 14 show groups of translator register relays which are selectively operated by the translator switch and pulse machine shown in Fig. 15 in accordance with the setting of the code re isters for determining the setting of the c ass, route and corn-' pensating resistance switches sho em in Fig. 9, the setting of the district selector and office selector switches shown in Fi s. 2 and 3 for setting the sequence switch 0 the district selector to determine the talking path through the repeating coil of the district selector; Fig. 15 shows a translator switch and a development of the pulse machine drum for setting the register relays; Fig. 16 shows diagrammatically some of the various types of connections which may be esmeans of the oflice sending mechanism an Fi 17 is a diagram showing the manner'in w llCll the several sheets of the drawing should be arranged to show as much of a complete organizationof circuits as is necessary to illustrate the manner in which connections may be established.

The calling subscribers line K is of the usual type provided with a transmitter, receiver and call-bell, and since it is assumed to be of the coin box type and terminates in a full mechanical exchange, it is also equipped with a coin box and with an impulse sending dia-l S, both'of the usual type.

The subscribers line terminates in an individual trunk finding switch of the well-known rotary step-by-step type, which through a plurality of wipers has access to a group of trunklines terminating in dis trict selector switches. The switch is provided with a stepping magnet for advancing the wipers over terminals of irunk lines in search of an idle trunk and for advancing the wipers around to normal position upon the release of the established connection.

The district selector switch 2.30. oilice selector 350, incoming selector 4550 and final selector 550 diagrammatically disclosed in Figs. 2 to 5 inclusive, are of the type shown and described in the patent to E. 13. Craft and J. N. Reynolds. No. 1,123,696, issued January 5, 1915. Each of the switches has a vertically disposed switch shaft pro vided with five sets of brushes, each brush set having access to a bank of one hundred terminals. upwardly, an updrive magnet is provided, which, when energized, presses the switch shaft against a constantly driven power drunnand for restoring the switch shaft to normal position a second downdrive ma net is provided, which, when energized,

presses the switch shaft against a second constantly driven power drum. For determining the particular set of brushes on the For driving the switch shaftlllil which oflfice the toll connection is obtained I in the usual manner.

If subscribers in manual oflices or distant n toll oflices desire connections with subscribers .in the full mechanical exchange, such less B connections are established through a cordposition in the full mechanical ,oiiice, the cordless operator receiving the .number of the desired subscriber from the calling subscriber, and through her keyboard and sender causing the setting of cordless incoming selectors and final selectors to select the line of the desired subscriber. With this brief description of the manner in which various connectlons may be established from and to subscribers lines in a full mechanical exchange, the method of establishing, certain of these connections by means of the office sending mechanism associated with the full mechanical exchange will be described more in detail.

It will first be assumed that the calling subscriber K desires to establish a connection with a subscribers line L in his own oflice. Thecalling subscriber upon initiat-' ing a callremoves his receiver from the switchhook and closes a circuit for the line relay 101 of the trunk hunting switch 100, which circuit may be traced from battery through the right-hand winding of relay 101, the innermost lower armature and back contact of cut off relay 102, over line con-- ,dlictor 103, through the substation ofsubscribers line K and thence back over' line conductor 104: to ground. at the upper armature and back contact of relay 102. -fllhe line relay energizes in this circuit and closes a circuit for the stepping magnet 105, which circuit may be traced from battery, through the winding and armature contacts of magnet 105, conductor 106, the lowermost armature and backcontact of relay 102, the right-hand armature and front contact of relay 101, conductor 107 and thence to ground through the wiper 108 and the normal terminal of the bank upon which this wiper is resting. Magnet 105, upon energizing, advances the wipers 108, 109, 110, 111, 112 and 113 to the second terminals of the respective banks to which they have access. As the second terminal which wiper 108 now engages is permanently connected to ground, magnet 105 continues to step the wipers to the third set of terminals leading to the first of the group of trunks to which the switch has access.

If the first trunk of the group is busy, there will be ground potential on the test terminal thereof appearing in the lowermost bank of the switch, and the switch will there fore continue stepping until an idle trunk is found, upon the test terminal of which, battery potential appears. When this battwain selector to which the first idle trunk extends,

through the inner left-hand armature and back contact of the sleeve relay 226, over test conductor 11 1-, Wiper 108, conductor 107, the lef -hand armature, front contact and "left-handwinding of relay 101, conductor 115 and thence to ground through both windings of relay 102. Relays 101 and 102 are then energized in this circuit. The energization of relay 102 opens the circuit of stepping magnet105 atits lowermost armature and back contact, and at its upper armature and front contact and intermediate ar- I mature and front contact, this relay extends theconductors 103 and 10 1 of the-subscribers line to the wipers 111 and 113 and thence to the trunk conductors 116 and 117 leading to the-selected district selector. Relay 102, at its intermediate armature and front con tact, closes a circuit extending through the left-hand winding of'sleeve relay 226, the normal contacts of the left-hand armature of slow releasing relay 227, the lower right hand contact of cam 203 (1 to 2%), sleeve conductor 118, wiper 109, Winding of message register magnet 119, conductor 120, the intermediate armature-and front contact of relay 102 and thence-to ground through the upper winding of relay 102. The sleeve relay 226 energizes in this circuit, but magnet 119 being margmal does not energize at r this line, over conductor 122, through wiperand the off-normal segment 123 to grounded battery. Wiper 112, through the grounded off-normal segment 124;, prepares a circuit extending over conductor 125 preparatory to restoring the finder switch 100 to normal whenrelay 102 becomes deenergized upon the termination of the connection. 1

Upon the energization of sleeve relay 226, a circuit is established for the line relay 228 of the district selector switch 250, which circuit extends from battery, through the right-hand winding of this relay, the, upper contacts of cam 20%, the right-hand armature and front contact of relay 226 and thence to' ground through the upper righthand contact of cam 205 (17 to 15). At its inner left-hand armature and front contact, relay 226 connects ground potential to the test conductor 1140f the selected trunk to mark the trunk busy to other line switches, and at the back contact of this armature, disconnects the source of battery potential, which up to the time the selector switch was switch' shaft to be employed, a tripping spindle is provided as described in the patent hereinbefore referred to. The final selector switch differs from the other selector switches in being provided with additional means comprising a second updrive magnet and driving drum for driving the switch shaft upwardly. The two updrive drums rot-ateat different speeds whereby the switch shaft is moved upwardly rapidly during brush selection and group selection and more slowly durin terminal selection.

The'translatorswitch TS shown in Fig.

15 is of the same type as the switch shown in the aforesaid patent, but is equipped with ten sets of brushes arranged in five pairs, the brush sets comprising each pair being arranged to be tripped together.

The sender finder switch SF shown in Fig. 2, the monitoring switch M shown in Fig. 6, the time measure switch TM shown in, Fig. 7, the register steering switch RS and the registers A, B, C, TH, H, T, U, ST, ST and ST shown in Figs. 11 and 12 are of the well-known step-by-step type, the wipers of which are advanced by stepping magnets. These switches are. all restored by being stepped forwardly into normal position,

-with the exception of sender finder switch ments being connected to a source of current through a common slip-ring. A pluralityofbrushes engage the several rows of segments and are arranged to be variously connected .to the contacts iii the ten banks of translator switch TS, through suitable distributing blocks (not shown) for conducting impulses of current from the several segments to the bank terminals of the translator switch.

For controlling the circuits associated with the several selector switches and the circuits of the office sender, auxiliary switches are provided. These switches may he of the type described in the patent to J. N. Reynolds and CJF. Baldwin, No. 1,127,808, issued February 9, 1915 and known in the art as sequence switches. Vith the exception of sequence switch 900 which serves as a class switch and switch950 which serves as a compensating resistance switch, all sequence switches are restored to normal position when'not in use. The switches 900 and 950 however, are maintained in the position in which they were last used.

The different pieces of apparatus employed in the system having now been briefly described, it is thought that a clearer understanding of the invention may be had from a description of the method of establishing connections. Referring to Fig. 16, certain of'the mechanism of an origlnating ofiice of a full mechanical exchange is disclosed to the left and above the dot-and-dash lines, and a plurality of terminating ofiices and lines terminating therein have been repre sented within the dotted rectangles at the extreme right of the figure- Some of the terminating offices have been represented as mechanical ofiicesand some as manual ofiiees, some of which ofiices are within the local area, while others are at distant points. Where offices are located at distant points, a subscriber in the originating oflice obtains connections with suchdistant oflices through tandem offices which have been represented within dotted rectangles in the middle portion of the figure. Throughout the figure the arrowheads indicate the direction of progress to and from the various substations disclosed therein.

If, for example, the calling subscriber K desiresto establish a connection with a sub scriber in his own office, he may do so by operating the district, oflice, incoming and final selector switches of his own oflicc. In a similar manner, connections may be established with other full mechanical oflices in the local area by means of the district and oflice selector switches of the originating.

office, and the incoming and final selector switches 'of the terminating full mechanical office. Connections to manual oflice in the local area are'made through the operation of the district and office selectors of the originating office, the line desired in the terminating manual ofiice being indicated on a relay call indicator at such cfiice. If the calling subscriber desires to establish a connection with a subscriber in a distant oflice it is then necessary to first establish a con nection through the district and oflice selector switches of the originating office with a mechanicaltandem oflice, from which lat ter office the connection is then further extended through a district selector at such tandem ofiice to the terminating ofiice which may be either a manual or full mechanical oflice. If the intermediate oflice is a manual office, then the calling subscriber through his district and ofiice switches first extends the connection to the intermediate manual tandem ofiice where the designation of the desired line is registered upon a relay call indicator. The operator at the tandem office then extends the connection to the distant manual ofiice in accordance with the usual manual practice. For establishing connections to toll points, the calling subscriber first causes the extension of a connection through his district selector to a special .A operators position and the A operator through a sender and district so- 

